[PATCH] spi: pxa2xx: Prepare for edge-triggered interrupts

From: Jan Kiszka
Date: Sat Jan 21 2017 - 04:06:38 EST

When using the a device with edge-triggered interrupts, such as MSIs,
the interrupt handler has to ensure that there is a point in time during
its execution where all interrupts sources are silent so that a new
event can trigger a new interrupt again.

This is achieved here by disabling all interrupt sources for a moment
before processing them according to the status register. If a new
interrupt should have arrived after we read the status, it will now
re-trigger the interrupt, even in edge mode.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Acked-by: Robert Jarzmik <robert.jarzmik@xxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
drivers/spi/spi-pxa2xx.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c
index 8c65bc1823f3..06ade434c083 100644
--- a/drivers/spi/spi-pxa2xx.c
+++ b/drivers/spi/spi-pxa2xx.c
@@ -785,6 +785,9 @@ static irqreturn_t ssp_int(int irq, void *dev_id)
if (!(status & mask))
return IRQ_NONE;

+ pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg & ~drv_data->int_cr1);
+ pxa2xx_spi_write(drv_data, SSCR1, sccr1_reg);
if (!drv_data->master->cur_msg) {
/* Never fail */